The invention relates to a longwall conveyor with a lantern pinion arranged on the machine roadway side and consisting of consecutive racks which bridge the conveyor trough faces and are attached with a slight clearance, whose individual racks have a plate-shaped plug-in element with teeth welded into them and are fixed via bolts in a guide slit formed by a preceding retaining plate and a support plate associated with the vertical roadway flange.
Such longwall conveyors are equipped with lantern pinions in order to enable the roll charger or other longwall machine to move through the longwall, i.e. pull itself forward or backward along the racks which form the lantern pinions. Different types of lantern pinions or racks are known for this purpose, depending on whether they are supposed to be arranged on the winning face side or on the rock face side. Overall, it is the objective to make do with relatively little equipment and with favorable construction dimensions, whereby the racks are usually also shaped and constructed in such a way that the longwall machine guides itself along them. Such lantern pinions are usually arranged on the rock face side or the coal face side. Also known are however designs operating with two lantern pinions.
German DE-OS 29 14 861.6 describes a longwall conveyor with racks consisting both of plates with a height approximating that of the longwall conveyor height as well as of tooth-like noses projecting laterally from the plate. The machine roadway is shaped to the correspondingly shaped racks. The individual racks are fixed to the longwall conveyor or its conveyor troughs. The disadvantage is that in the case of tooth wear the entire rack must be replaced, requiring, due to the described connection, a significant expenditure of labor
German DE-OS 37 03 384 0 describes racks screwed with the L-shaped machine roadway to the conveyor trough. The teeth and the bridge that is practically set onto the L-shaped machine roadway form a complete unit which can be manufactured and used as such in the form of forged parts. The machine roadway in its entirety is connected in the area of the conveyor trough connection via a toggle connection to the next machine roadway, resulting in a certain mobility. But in the case of rack wear or other repairs, the entire L-shaped machine roadway here also must be disassembled and reassembled subsequently. The expenditure is large. The described assembly and disassembly expenditure is also large for the longwall conveyor according to German DE-PS 37 00 489. Only smaller tooth groups have been provided for a better replacement; but even this does not reduce the assembly expenditure.
German DE-GM 93 11 553 in contrast describes a longwall conveyor in which optimum guidance of the roll charger is achieved while maintaining the tooth pitch, since the corresponding lantern pinion is composed of racks that are so long or so short that in each case a rack element bridges the conveyor trough faces. Since they are attached with a slight clearance, the tooth pitch is always ensured. Assembly and disassembly are facilitated in that the racks consist of a plug-in element and teeth welded into them, whereby these plug-in elements which form the racks are inserted into a slit from the top and are then fixed by way of bolts, whereby said slit is formed by a retaining plate and a support plate that are welded at a distance from each other to the horizontal flange of the machine roadway. The bolts are pushed into corresponding bores and are then fixed by way of cotter pins which can be hammered out towards the bottom through corresponding bores, even passing through the roadway, if the rack is supposed to be removed. The disadvantage here is the attachment of these bolts by way of cotter pins, since they require suitable bores and guide slits that reach far enough. Another disadvantage is that the vertical parts forming the guide slit must be welded to the roadway, thus requiring a certain amount of preliminary work aboveground and otherwise making assembly underground more difficult. But in particular, the individual parts must be brought underground in order to undergo final assembly into a complete conveyor trough or the respective partial lengths there.